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;;;; lazybones.lisp
(in-package #:lazybones)
;;; DYNAMIC VARIABLES
(defvar *request* nil
"Dynamic Variable holding the current request object. Dynamically
bound and available to each handler. The exact object bound to
*request* varies according to the current backend.")
(defvar *response* nil
"Dynamic variable holding the current response object. Dynamically
bound and available to each handler. The exact object bound
*response* varies according to the current backend. ")
(defvar *app* nil
"Dynamic variable holding the an APP instance. Dynamically bound by
RUN-ENDPOINT so that it is available if needed in request handlers.")
;;; LAZYBONES CLASSES
(defclass app ()
((name
:reader app-name
:initarg :name
:initform (error "Appname is required")
:type symbol)
(version
:reader app-version
:initarg :vsn :initarg :version
:initform "0.0.1"
:type string)
(endpoints
:accessor app-endpoints
:initform nil)))
(defclass endpoint ()
((method
:reader endpoint-method
:initarg :method
:initform :get)
(template
:reader endpoint-template
:initarg :template
:initform (error "endpoint template required"))
(dispatch-pattern
:reader endpoint-dispatch-pattern)
(handler-function
:reader endpoint-request-handler)
(documentation
:reader endpoint-documentation
:initarg :doc
:initform "")))
(defun routekey-term-match-p (pattern-term routekey-term)
"Internal helper function. Returns T if both arguments are strings
and they compare with STRING-EQUAL. Otherwise, PATTERN-TERM is
assumed to be a route variable representation, in which case T is
returned, indicating that the variable should bind to anything."
(if (stringp pattern-term)
(string-equal pattern-term routekey-term)
t))
(defun matches-routekey-p (pattern key)
"PATTERN is a list, each member of which is a string or a variable
representation. PATTERN will have been generated by
PARSE-ROUTE-STRING-TEMPLATE.
If there are no variables in PATTERN, MATCHES-ROUTEKEY-P returns T
or NIL.
If there are variables in the pattern, MATCHES-ROUTEKEY-P returns a
list of values, in the case of success, or NIL in the case of failure."
(when (= (length pattern) (length key))
(loop for pterm in pattern
for rterm in key
for matchp = (routekey-term-match-p pterm rterm)
unless matchp
return nil
when (listp pterm) ; looks like (var) or (var value-parser)
collect (if (second pterm)
(funcall (second pterm) rterm) ; parse value from rterm if we can
rterm) ; otherwise use rterm string
into arguments
finally (return (or arguments t)))))
(defun find-endpoint (app &optional (request *request*))
(find-endpoint-matching-key
app
(request-method request)
(request-routekey request)))
(defun find-endpoint-matching-key (app method key)
"Returns a list. NIL represents failure to find match.
Otherwise the result is (ENDPOINT . ARGS) where ENDPOINT is an
endpoint instanceq and ARGS is a list of arguments to pass to
ENDPOINT's handler function."
(loop for endpoint in (app-endpoints app)
for match = (and (eql method (endpoint-method endpoint))
(matches-routekey-p endpoint key))
when match
return (cons endpoint (when (listp match) match))))
(defparameter +http-methods+
(list :get :head :put :post :delete :patch))
(defun url-path->request-routekey (path)
"A routekey is used to match urls to endpoints that handle them."
(str:split #\/ path))
(defun request-routekey (request)
(url-path->request-routekey
(request-path request)))
(defun parse-route-string-template (template)
"Routes are of the form
/foo/bar/<<variable>>/blah
/foo/bar/<<var parse-integer>>/blah
On success returns things like:
(\"foo\" \"bar\" (VARIABLE) \"blah\")
(\"foo\" \"bar\" (VAR PARSE-INTEGER) \"blah\")
Returns NIL on failure"
(cond ((equal "" template) nil)
(t
(when (search "//" template)
(warn "The proposed route ~s contains a double forward-slash (//), is this intended?"
template))
(when (a:ends-with #\/ template)
(warn "The proposed route ~s ends with a forward-slash (/), is this intended?"
template))
(unless (eql #\/ (elt template 0))
(warn "The proposed route ~s does not begin with a forward-slash, is this intended?"
template))
(loop for field in (str:split #\/ template)
for var? = (parse-route-variable-string field)
when var?
collect var?
else
collect (string-downcase field)))))
(defun parse-route-variable-string (string)
"A route variable string looks like <<foo>> or <<foo bar>>
In the case of a successful parse, a list of one or two symbols is
returned. These symbosl are created using read-from-string, which
allows for these symbols' packages to be specified if desired.
Returns NIL on failure."
(when (and (a:starts-with-subseq "<<" string)
(a:ends-with-subseq ">>" string))
(destructuring-bind
(var-name . decoder?)
(re:split " +"
(string-trim " "
(subseq string 2 (- (length string) 2))))
(if decoder?
(list (gensym var-name) (read-from-string (first decoder?)))
(list (gensym var-name))))))
(defun run-endpoint (endpoint args request response app)
(let ((*request* request)
(*response* response)
(*app* app))
(apply (endpoint-request-handler endpoint) args)))
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